Experiments with Monster Girls
by openbookworm
Summary: This is a series of smutty fanfics based around the relationships between the biology teacher Takahashi Tetsuo and his monster girl students. Here you'll find out what might happen if he was more willing to cross the boundaries between teacher and student. Please enjoy the fic and remember to fave, follow, and review. Definitely Lemon content. You have been warned.


Machi Kyouko was an ordinary high school girl who just so happened to be a dullahan, a type of demi-human whose head exists separately from their body. Apart from that minor hiccup, there was no difference between her and the next student. Especially when the next students were her friends, Takanashi Hikari the vampire and Kusakabe Yuki the yuki-onna.

Currently the three young demis were holding an idle conversation in an empty classroom. They didn't bother to keep their voices down as school had ended for the day and the only students left were those with club activities or those accompanying a teacher like they were.

Talking was made a bit awkward by the fact that Machi's head was currently nested on top of a desk. She also couldn't turn her heard to face the current speaker, as her hands were otherwise occupied.

Earlier that day, Machi had volunteered to help Takahashi-sensei with an experiment that he had thought up. He was interested in seeing just how much information her body could transmit to her head without both being in the same room. So Takahashi-sensei had led her body away to another room while her friends volunteered to keep her head company.

Machi felt a bit guilty as she couldn't pay her full attention to the conversation with her friends. She kept getting distracted by the rough texture of Takahashi-sensei's hand wrapped around her fingers as he guided her sightless body. But she gamely tried to respond quickly to any comments directed her way, even as she worried about how sweaty her palms were getting.

Eventually the teacher and student reached their destination. She felt a short pause as Takahashi-sensei stopped in the hallway to open a door, and another as the door was closed behind them, then she was guided to a chair and made to sit with a gentle press on her shoulders.

Machi tried to sit up as straight as she could, while she waited for the experiment to begin. Her heart almost jumped out her throat when she felt his hand lift her arm by the wrist and hold it in place with her palm facing the ceiling. Then with a gentle touch that tickled her soft skin, Takahashi-sensei began to draw out some words on the sensitive surface of her palm.

'Can you read this?'

Machi almost said 'yes' before she remembered the separation between her head and body. She softly coughed hide her embarrassment and thought of another way to show her agreement. With a short bow at the waist, Machi managed to convey her understanding.

'Good. I will now begin the experiment. If at any time you feel uncomfortable and wish to stop, please stand up.'

Another dip of her waist signalled her understanding and Machi waited for him to take the first step.

Takahashi-sensei let go her arms and slowly started to move. Due to her special constitution, the spatial sensitivity of Machi's body was well-developed and she could feel Takashi-sensei walk around her chair to stand behind her. Machi gulped as she felt the presence of her teacher looming over her and she almost jumped out of her seat when his hands dropped onto her collarbones.

Suppressing the thrill of such intimate contact with the man she had a crush on, Machi tried not to fidget and resisted the urge to lean backwards and get closer to him. When Takahashi-sensei's fingers began to apply a strong, yet gentle pressure to her stiff shoulders, Machi had to stifle a soft gasp that threatened to escape her lips.

The small sound drew her friends' attention and she had to smile awkwardly and try to dismiss it as a simple cough. Meanwhile, Takahashi-sensei continued to knead the stiffness from of her shoulders, working out the knots in the muscle and relieving the tension that Machi had accumulated over a day of studying.

For a girl her age, Machi possessed a very impressive bust, one of the largest in her class. Despite the envy it drew from some of the other schoolgirls who had yet to experience the joys of puberty, her large breasts were an inconvenience in her daily life. The weight of her chest and the need to carry her head everywhere she went placed a lot of stress on Machi's shoulders, and the release of this stress from Takahashi-sensei's shoulder massage made her feel as though she had just set down a heavy load.

His rough callouses pressed deeply into the aching spots on her nape and collar. After a brief burst of pain, his fingers left behind a comforting sense of relief. Machi soon let go of her initial nerves and her rigid posture melted into a more comfortable position.

If it weren't for the fact that she was still trying to carry on her chat with Hikari and Yuki, Machi would have been tempted to simply close her eyes and luxuriate in the warmth spreading from Takahashi-sensei's rugged hands.

Once all the muscles in her shoulders were nice and loose, Takahashi-sensei's roaming fingers fell from her shoulders to her upper arms. Machi's breath hitched and she felt a resurgence of nervousness as she registered where his hands were now resting.

Due to the constant workout that her arms received from carrying her head wherever she went, they had a noticeable layer of muscle. When Machi was younger and had yet to come into a large chest, she was often mistaken for a boy due to her broad shoulders and short, brown hair. Even though she had grown into a beautiful young woman, she was still sensitive about how her muscles made her appear more masculine.

However this insecurity was soon assuaged as Takahashi-sensei's fingers worked their magic pm the rigid flesh of her upper arms. He showed no hesitation as he caressed her smooth skin and the effects of his touch left Machi too happy to care about which parts of her body he was handling. Shivering from the pleasure and struggling to maintain a stoic expression, Machi trembled under Takahashi-sensei's experienced hands.

When the expert massage finally ended, Machi's arms were left hanging bonelessly by her sides as a flood of relaxation coursed through her upper body. This left her defenceless when Takahashi-sensei took the initiative to begin the next step of the experiment.

Takahashi-sensei seized Machi's forearms and pulled them both behind her back until he could hold them together in one hand. With his free hand he began winding a length of thick rope around both arms until her hands were bound behind her back, on the other side of the chair's back-support.

Machi realized what was happening too late to offer any resistance. A thrill of fear, mixed surprisingly with anticipation, ran up her spine as Machi realized that she was now tied up and at Takahashi-sensei's mercy. Part of her was concerned about where things were going and told her to stand up and end the experiment, but a fire had been lit inside of her at his touch and she felt an irresistible temptation to let things go farther.

Takahashi-sensei circled around her until he was standing in front of her once more. Despite the fact that her head was in a different room room, Machi could somehow tell that his smouldering gaze was resting on her breasts. With her arms tied behind her back, her chest was thrust forwards, straining the thin cloth of her school uniform.

Machi decided to let things play out as they were and she felt a thrill of naughty excitement at keeping the events happening in the other room a secret from her friends. Even as she struggled to keep up with what her friends were saying, Machi's mind was racing as she went over some fantasies of what might happen next.

Her frantic thoughts were cut to a halt when she finally felt a pair of hands cup her breasts. The touch of Takahashi-sensei's hands on her chest filled Machi with nervousness, tinged with anticipation.

Were they really going to cross the line between teacher and student?

She had never had anyone subject her to such blatant seduction, so she wasn't sure what to do or how to react. But this was Takahashi-sensei, the man she fell in love with at first sight, and she was flattered that he had chosen her as the target of his attention. So when his fingers started groping her chest, Machi bit her lip and tried to keep her cool despite a red flush flooding her cheeks.

Takahashi-sensei had the strong hands of an athlete or construction worker, rather than the biology teacher he was supposed to be. When he had last carried her head, Machi noticed that his hands were at least twice the size of her own. She had felt very secure within his grasp, but she also noticed that whenever he held her, he made sure to use a gentle touch. Even now, with his fingers sinking into the springy tissue of her breasts, Takahashi-sensei kept his hands to a firm and gentle pressure.

Despite the barrier of clothing that lay between his hands and her skin, Machi could sense a wave of heat transmitting from the surface of his hands and spreading into her body. With every beat of her pounding heart, she could feel warmth building up in the pit of her stomach until she was squirming in her seat from the heat.

Once Takahashi-sensei finished examining the weight and texture of her breasts to his full satisfaction, his hands moved upwards to undo the line of buttons stretching from her collar to her waist. A flash of mortification ran through Machi's head as she realized her mistake. If she had seen that this was coming, she would have worn something sexier than the plain grey sports bra that she had worn to school today.

Not that she had any lingerie, but perhaps something with a few laces at least?

In any case, it was too late for her to change, so Machi simply tried to keep still as Takashi-sensei stripped her. Soon enough, her shirt fell open, exposing her naked chest to his ravenous sight. The experience of flaunting her bare skin in a school classroom was embarrassing, but the fact that it was Takahashi-sensei looking at her made it seem all the more exciting.

After soaking in the sight of the beautiful half-naked girl, Takahashi-sensei got back to the task at hand and pulled her sports bra down so that it was now bunched up beneath Machi's perky breasts.

Without the restraining effect of her sports bra, Machi's tits looked larger than ever. They were at least a D-cup already and seemed to be growing every day. Their heavy weight caused them to sag slightly, but at her tender age they appeared round and firm even without the support of her bra. Her nipples were hidden within the dark brown flesh of her coin-sized areolae, yet the arousal incited from baring her naked body to the man she loved had swollen the tips of her stiff brown nipples and they were now peeking out from their caves.

At the sight of her beautiful breasts, Takahashi-sensei seemed to lose control of his lustful desires. His hands immediately began roughly groping Machi's pale flesh, and without the protective barrier of her clothing, the sensitivity of her chest was at its peak. Machi arched her back from the electric shock of his touch and unconsciously thrust her breasts further into his spirited grip.

Takahashi-sensei kneaded Machi's large mounds of flesh between his thick fingers, moulding their shape like clay. His rough treatment of her breasts aroused a response that Machi had never felt before. As his hands roamed over each part of her chest, the enflamed sent up signals of pleasure that had Machi shaking in desire.

Even as he continued to explore the sensitivity of her breasts, Takahashi-sensei began to draw circles with his thumbs over the darker flesh of her areolae. Machi's nipples began to swell in response to the attention and they slowly began to emerge from their hiding places. However Takahashi must have deemed their speed unsatisfactory as he bent his head, wrapped his lips around a nipple, and sucked out the remaining length before repeating the process on the other side of Machi's chest.

Machi's dark, puffy nipples now stood stiffly at the peaks of her breasts, standing a clear sign of her arousal. Their responsiveness was soon tested when Takahashi-sensei seized the two brown tips and rolled her twin nubs of flesh between the rough finger-pads of his thumbs and index fingers.

Machi was barely able to hold back the cry of pleasure that erupted from Takahashi-sensei thorough mauling of her chest. The mounting waves of pleasure she felt rising in her loins soon exceeded anything she may have felt before during her own private sessions of masturbation.

In response to her growing desire, a wash of heat was spreading outwards from the flames on Machi's neck. The skin of her chest was soon glowing from this internal heat and a scattering of nearly invisible freckles could now be seen standing out against her reddening flesh. The heat also spread upwards into her face and Machi was forced to fend off concerned inquiries from her friends with increasingly unconvincing protests that she was not 'running a fever'.

Before Machi could reach the very summit of her climax, Takahashi-sensei's hands withdrew from her chest. Machi almost protested the abrupt halt to their foreplay before she remembered which room her head was in. If it wasn't for the fact that her arms were still tied behind her back, she would have grabbed his hands in hers and pulled them back onto her breasts to continue their fondling.

However Takahashi-sensei wasn't cruel enough to simply end the experiment there and leave his beloved student unsatisfied. He had merely decided to move on to another erogenous zone of her body.

Machi gave off a sharp yelp of surprise when his hands seized her hips and pulled them to the edge of the seat, so that she was now sitting in a lower angle to the back of the chair. By placing Machi in this reclining position, Takahashi-sensei had made it easier to access her lower body.

He flipped up Machi's skirt to reveal her plain cotton panties and the wet stain running down the length of her covered slit. Before Machi could fully register the shock of this indecent exposure, Takahashi-sensei seized the damp cloth in his fist and tore it away in one go, exposing her bare mound and the traces of arousal that were leaking from her blooming petals.

Machi's special ability meant she was able to see her vagina even without the use of a mirror. This made shaving her pubic region an easy task, so the skin surrounding her lower lips was immaculately pink and hairless. This made it easy to see the effects of Takahashi-sensei groping her chest, as the dripping fluids spread from her lower lips to cover her flushed skin in a shining sheen of slippery liquid.

Judging that her folds were already sufficiently lubricated, Takahashi-sensei decided to prepare Machi for the next stage of the experiment.

Takahashi-sensei reached down and rubbed a finger along her swollen labia, covering the digit in her natural lube. Then he placed the tip of his finger at the entrance to Machi's pussy and slowly began to slide his finger into her tight canal. Despite the moisture coating her inner walls, Takahashi-sensei barely managed to sink his finger down to the lower knuckle before it grew too tight to continue.

Machi's focus was fully concentrated on the strange sensation of Takahashi-sensei's thick finger slipping into her folds, his rugged digit felt so different to her own slim appendages. Her lower mouth clenched tightly around the intruding index as if it was trying to squeeze his finger back out, but Machi could feel that Takahashi-sensei's strength was easily keeping it in place.

Rather than removing his finger from the tight vice closing around it, Takahashi-sensei slowly twisted it in place, making use of Machi's own wetness. He ran the tip of his finger around the walls of her pussy, brushing over all the sensitive folds that lay just inside the entrance. When Takahashi-sensei brushed a certain spot that lay roughly beneath the centre of Machi's pubic bone, he felt a convulsion run through her hips and he knew that he had found his target.

He began to focus his attentions on that one spot. Showing off his years of experience, he traced around the G-spot with the tip of his finger before gently stroking the sensitive bundle of nerves. It became slightly difficult to continue when Machi began to jerk in place as the pleasure grew too much to handle, but a firm hand pressing down on her taut stomach pinned her back into place.

Machi was rendered unable to run from his constant attacks at her weak point and she was forced to silently endure the inescapable pleasure. When the pressure of her walls finally loosened around him, Takahashi-sensei knew that she was ready for more.

Machi couldn't remember ever having felt so good. It was getting harder and harder to concentrate on keeping her composure and she was losing control of her own expression. At this rate it wasn't only a matter of time before Hikari and Yuki figured out that something was going on.

If it wasn't for Takahashi-sensei holding her in place like a life fish on a chopping board, she may already have fallen off her seat as the love juice leaking from her pussy had covered her seat in a slippery film of her own fluids. When Takahashi-sensei slipped a second finger into her lower lips, Machi finally lost control of her voice and let out a breathless cry of joy.

As his thick fingers curled upwards and repeatedly raked across her G-spot, Machi felt her breaths shortening into ragged gasps from the pressure building up in her loins. The walls of her pussy tightened once more as a sign of her impending climax and Machi's panting grew increasingly loud and hoarse. Takahashi-sensei eventually pushed her over the edge by raising his thumb and pinching down on her clitoris and G-spot at the same time.

With a great shuddering inhale of air, Machi silently ejaculated and her body shook in place as the aftershocks of her orgasm ran their course throughout her entire body. All other thoughts vanished as an explosion of ecstasy went off inside her head, leaving it completely blanks. All pretence of being part of the conversation was lost as her fluttering eyelids and drooling mouth left Machi looking half-asleep.

As Takahashi-sensei withdrew his soaked fingers from her twitching folds, he made sure to test the widening of her entrance by stretching her lips apart. In the aftermath of her orgasm, Machi had lost all control of her pelvic muscles and it was easy to stretch the mouth of her pussy. Thin strands of pearly liquid stretched across the gap between his fingers, but Takahashi-sensei was able to peek insider her hole. He could see the ridges of Machi's inner walls stretching and twitching slightly as the lingering aftershocks ran through her body.

With how limp her body felt, Machi could barely show any reaction when Takahashi-sensei reached down to grab her ankles and lift them above her head. Apart from a small grunt of released breath as she was curled onto herself, Machi behaved exactly like a posable doll as Takashi-sensei lined himself up for entry. If it wasn't for the white fuzz lingering inside her head, Machi might have felt some trepidation for what was coming next.

Machi might not be able to see what was going on, but she could certainly feel it when the broad head of Takahashi-sensei's penis began to press against her lower lips. Intimidated by the size of the appendage demanding entry into her sex, Machi shivered and her thighs instinctively tried to close up for her own protection. But Takahashi-sensei's firm grip on her ankles kept her legs from squirming as he leaned forward in preparation for his approach.

When he finally began to push forward past her outer petals, Machi felt a nagging discomfort as her tight hole stretched to encompass her thick girth. Even with the stretching from his fingering, this was Machi's first experience with a real dick. Takahashi-sensei kept his advance to a slow pace, but he was relentless in driving his red-hot shaft into her tender body.

The pulsing muscle of Takahashi-sensei's rock-hard penis enflamed the surrounding flesh as it pushed forward. Its passage was aided by the slippery walls of Machi's pussy. Her fold tightened around his cock as if they were trying to smother its heat, but their squirming only drew him in deeper.

Eventually Takahashi-sensei reached the limit of how far he could go. Despite having an inch at his base that had yet to sink into Machi's soft embrace, the tip of his cock-head was now kissing the mouth of her womb. An outline of his dick could be seen pushing up against the flesh of her stomach.

Machi had never felt so full in her entire life. Takahashi-sensei was huge, almost too huge, and the farther he got inside her, the more it seemed as if a heavy weight was pressing on her diaphragm. Gasping for air, Machi tried to adjust to the thick rod of flesh that was now stretching her insides, but as Takahashi-sensei started to pull back out she lost her breath once more. The friction of his movements sent a shudder of ecstasy coursing through her prone frame and washed away the discomfort of his penetration.

With her velvety walls clutching tightly at his penis, Takahashi-sensei had to shift his grip downward, pressing on her thighs, to stop Machi from falling off her chair as he pulled out. Once he was almost unsheathed, he violently thrust himself back into her folds, igniting another surge of pleasure that had Machi curling her toes in delight and biting her lower lip to keep herself from screaming.

Picking up his speed, Takahashi-sensei began to thrust himself into Machi at a steady rhythm that had Machi drowning under waves of pleasure. As he relentlessly pounded Machi into the chair, her body was shaking from the force of his movements. The flesh of her ass and thighs rippled sexily as their hips collided against each other, and Machi's breasts bounced freely on her chest with each smack of flesh on flesh.

The flames on Machi's neck sputtered wildly as the mounting ecstasy washed all other thoughts from her head and replaced it with a hedonistic desire for more. If she wasn't getting the breath driven out of her from the hard fucking, she would have been screaming for him to go faster. As it was, her friends could see Machi's eyes roll up in her head as her mouth opened in a rapturous cry of euphoria.

Despite being pinned immobile in her seat, the tight walls of Machi's pussy twisted violently as they attempted to milk Takahashi-sensei's cock. A series of minor orgasms continually wracked her body and the ejaculation leaking from her sex were churned into a froth by the frenzied pace of their lovemaking. Machi was about to lose her mind from the never-ending pleasure when Takahashi-sensei decided that it was time to shift position.

Takahashi-sensei stopped pressing down on her thighs and instead wrapped his arms around her shaking body. With one hand tightly gripping her rear and the other supporting her shoulders, he lifted Machi off the chair. As he did so, the rope holding her arms together slipped off, revealing that it had not been securely tied off.

Though Machi was one of the tallest girls in her class, she seemed almost weightless in his arms as Takahashi-sensei easily supported both of them. With Machi being pulled into an upright position, the shift in position led Takahashi-sensei's thrusts to rub up against a different set of sensitive ridges in Machi's tight coils. With the adjusted angle and the addition of Machi's weight pressing down on his dick, Takahashi-sensei was able to sink the remaining length of his dick, right up to the base, into her pussy.

It may have been due to Takahashi-sensei managing to hit another sweet spot, or Machi's own poorly-concealed fetish for hugs, but as Takahashi-sensei pulled her in close, she was pushed over the peak once more and lost consciousness in a final explosive climax. The walls of her pussy clenched tightly around Takahashi-sensei's hard cock and a flood of her juices poured down her bare thighs, staining his pants and dripping onto the classroom floor. Without Takahashi-sensei propping up her shoulders, Machi would have fallen backwards due to a loss of control.

Though Machi may have reached her limit, Takahashi-sensei wasn't done with her yet. Tightening his grip on her curvy rear, he continued to thrust upwards into her shivering and boneless body. Even without her conscious thought, Machi's arms and legs instinctively wrapped themselves around Takahashi-sensei's broad torso. Impaled onto his sturdy dick, her whole body bounced up and down as her breasts ground against his hard pecs.

With each upwards thrust Takahashi-sensei stretched Machi's insides even more, leaving a permanent imprint of his dick inside her body. His aggressive assault on her already overwhelmed pleasure systems overcame any resistance that she might have left to his intrusion. The mouth of her womb opened up in preparation and when Takahashi-sensei finally came, her insides were painted white with his seed.

Takahashi-sensei's legs finally gave out from the force of his ejaculation and he collapsed onto the classroom floor with Machi's senseless body resting in his lap. In the other room, Machi's eyes were closed as she had fallen into a dreamless sleep. Even while unconscious, her limbs tightened their hold on her beloved teacher and their combined love juices slowly leaked around the base of his shaft.

As Hikari and Yuki looked down on the head of their unconscious friend, a flash of envy went unseen in their eyes as they waited for their friend to wake up.

'Next time,' they promised, 'it will be my turn.'


End file.
